Hello all, I received an approval notice for my GC today. However it was a form of I-181 not a I-797. It said I should get my GC in mail by 3 weeks. It never mentioned anything about getting my passport stamped in a local INS office. How come they mail me I-181 first? Is this normal? Do I have to get my passport stamped before they will mail me the GC? Does anyome know? Thanks for any comments.